The following relates generally to wireless communication, and more specifically to multi-beam and single-beam discovery reference signals (DRS) for shared spectrum.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems, (e.g., a Long Term Evolution (LTE) system, or a New Radio (NR) system). A wireless multiple-access communications system may include a number of base stations or access network nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).
Wireless communication systems may operate in millimeter wave (mmW) frequency ranges, e.g., 28 GHz, 40 GHz, 60 GHz, etc. Wireless communications at these frequencies may be associated with increased signal attenuation (e.g., path loss), which may be influenced by various factors, such as temperature, barometric pressure, diffraction, etc. As a result, signal processing techniques, such as beamforming, may be used to coherently combine energy and overcome the path losses at these frequencies. Due to the increased amount of path loss in mmW communication systems, transmissions from the base station and/or the UE may be beamformed. That is, wireless communications between two wireless nodes, e.g., between a base station and a UE, may use beams or beamformed signals for transmission and/or reception.
Critical communication signals (e.g., reference signals for discovery or synchronization) in shared spectrum communication systems (e.g., systems with multiple operators using the spectrum) may require contention procedures such as channel sensing for fair access to the shared spectrum. Further, frequent or periodic/semi-periodic transmission of such signals may cause overcrowding and result in coexistence issues. Improved design and techniques for reference signaling in shared spectrum communication systems may thus be desired.